Patent GB-1448460-A (GB)
Title: Method and apparatus for making an filling bags
IPC: B31B23/00
Filed: 1973-11-23
Abstract: 1448460 Making bags; seaming V ROSSI 23 Nov 1973 [23 Nov 1972] 54564/73 Heading B5D [Also in Division B8] In a machine for forming, filling and closing bags, a series of bags carried on a first step-wise movable conveyer 13 are transferred to a stepwise rotatable turret 28, whose frequency of stepwise movement is half that of the first conveyer to facilitate the transfer of two bags at a time during each dwell period of the turret, and are then carried by the turret past a filling station Z at which the two bags are simultaneously filled during a dwell period of the turret prior to discharge into containers 58 of a further stepwise movable conveyer 59 at an unloading station X. The conveyer 59 transports the filled bags to a transfer station W at which two groups of four bags are placed in one of a set of receptacles P of a second stepwise rotatable turret 70, said turret carrying out one indexing step for every four indexing steps of the first turret 28 and for every eight indexing steps of the first conveyer 13. The turret 7c carries the bags past a top sealing station and thence to an unloading station H. The bags are initially produced by severing sections from a continuously formed tube by means of fixed and rotary knife elements 11A and 11B, which are disposed above the first conveyer so that the severed sections fall under gravity into pockets 14 of the conveyer 13, which then transports the sections past a bottom sealing device G. Forming the continuous tube from which the bag forming sections are severed, Figs. 3, 4 and 5 (not shown).-A laminated web S comprising a heat-sealable polyethylene layer is continuously-driven by rolls 8 and 9 over a mandrel 2 formed by spaced plates 3A and 3B and is folded into a side-pleated tube by folding and pleating elements 300, 700, 301 and 3. The overlapped longitudinal web margins are heatsealed by a resistance heated bar 4 carried on a jack-operated cranked arm 5A. A spring-biased compression roller is mounted on the bar. Conveyer 13, Figs. 1 and 2 and Fig. 6 (not shown).-The conveyer 13 follows an irregular pentagon-shaped path over rolls 27, 27A and 27B and comprises chains 14B mounting threesided containers or pockets 14 in which the cut tube lengths are received and held by parallel bars 16. The conveyer intermittently feeds the cut tube lengths past a bottom sealing device G and thence to the first turret 28. The bottom sealing device G, Fig. 2 and Fig. 7 (not shown).-The bottom of the cut tube lenths are sealed whilst retained in the pockets 14 between a heated fixed welding bar and a co-operating pivoted bar 18, which is moved against the fixed bar during swell periods in the conveyer movement through drive linkage 21. The bars are of such a length that more than one tube end is clamped therebetween at each bar closure so that the bottom of each bag undergoes more than one sealing action. A weld cooling bar section 17B and 18B is provided. Transferring the formed bags to the first turret 28, Figs. 1 and 2 and Figs. 8, 9, 9A (not shown).-Between the rolls 27A, the conveyer 13 positions two bags in line adjacent two pairs of reciprocable jaws 29, each pair of which grips the sealed bag bottom and transfers the bag from the pocket to the turret where one top side of the bag is held against the turret face by a gripper 41 of a gripper and spreader unit 40. The jaws are pivotally carried on a bracket 29 which is reciprocated by means of a cam-actuated parallelogram linkage 34. The jaws are moved to and from each other by means of a jackoperated rack 31 engaging jaw pinions 30. A lever 39, which retains the bags in the conveyer pockets at the transfer station, is tripped to the release position when jaws are moved towards the turret. The gripper 41 is pivotally mounted on the turret and is associated with a camactuated spreader 42 mounted on a parallelogram linkage 46, 51 and acting to spread the bag mouth when clamped on the turret. The turret is indexed past a bag bottom squaring device to a filling station wherein metered weight quantities are fed to the bags prior to movement to an unloading station X. The unloading station X and second conveyer 59, Fig. 2 and Fig. 10 (not shown).-At the unloading station X, the gripper and spreader units are released to allow the filled bags to fall two at a time into coupled open-ended containers 58 carried on conveyer chains 59A and are compacted by engagement with a surface 60 extending along the conveyer path to the transfer station W. The conveyer is intermittently advanced one step equivalent to the length of a coupled container for every two advancing steps of the conveyer 13 to permit two bags at a time to be transferred thereto. The transfer station W, Figs. 11 and 12 (not shown).-At the transfer station W after each time the conveyer 59 has moved forward two steps to position four filled bags in a line a retractable portion 60a of the surface 60 is withdrawn to allow the four bags to fall simultaneously into one chamber 62B of a twochambered receptacle 62. The receptacle is reciprocated laterally and the process repeated to allow four more bags to be deposited in the other chamber 62A. The receptacle incorporates jack-operated side and end plates 64 and 65 for squaring and compacting the bags. The movable base 67 of the receptacle is opened and the set of two groups of bags discharged into one of a plurality of vessels 69 mounted for vertical displacement on the second turret 70, which carries the bags to the top sealing device 88. The top sealing device 88, Figs. 1C and 2C.- At the top sealing device a ram 301 raises a bag-containing vessel 69 in the turret into sealing engagement with a bell hood and the air is evacuated. The open bag tops are then collectively sealed between fixed and movable bars 305 and 306. The ram is then lowered and the turret indexed to an unloading station H. In a modification, Figs. 13 and 14 (not shown), the vessels 69 on the turret 70 are modified to incorporate pivotal top compactor plates 74, 80, and 81 operable to vertically compact the bags.